The study looked at the potential for microbial contamination from hand drying and the potential risks for airborne microbe dispersal, particularly if hand washing is sub optimal. Four different hand drying methods and three different test models were used to determine differences between the drying methods and their capacity to disperse microbes on the hands of users to other occupants of public washrooms and into the washroom environment.

Paper towels, a textile roller towel, a warm air dryer and a jet air dryer were compared using three different test models: acid indicator with lemon juice, yeast, and bacterial transmission from hands when washed without soap. The peer-reviewed study was published in the March 2015 edition of the Journal of Hospital Infection.

A jet air dryer dispersed liquid from users' hands further and over a greater range - up to 1.5 metres - than other hand drying methods. The jet air dryer also led to the greatest dispersal of microbes into the air at both near and far distances for each of the tested models. Levels recorded at the drying device revealed an average of 59.5 colonies of yeast for the jet air dryer compared with an average of just 2.2 colonies of yeast for paper towels.

At a distance of 0.2 metres jet air dryers resulted in 67 colonies compared with only 6.5 for paper towels. At a distance of 1.5 metres the jet air dryer recorded 11.5 colonies of yeast compared to zero for paper towels.